Language: Philippine Spanish
Source: Secondary reference
Bolo simply means knife and is usually used to describe a wide range of Philippine single-edged machete-like tools and weapons.
The term comes from the Spanish and its use is similar to the word parang of the Malay world.1
There is an informative Wikipedia Article on this weapon.
A very good Philippine bolo from Luzon.
1. Stone, G.C.; A Glossary of the Construction, Decoration and Use of Arms and armor, 1934. Reprint by Dover, 1999, p. 124 - 125.